Micro-controller + RF module for Capsule Size circuit

Discussion in 'Embedded Systems and Microcontrollers' started by zetinal34, Mar 21, 2012.

  1. zetinal34

    Thread Starter New Member

    Mar 21, 2012
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    Hi all,

    I am currently doing the project on gas sensor capsule.
    I'm very new to micro-controller and rf module.
    I really need help and advice on what micro-controller and transceiver I should use for this project

    The requirements are as below
    -Small dimension (Both micro-controller and transceiver)
    - Low power
    - Transmission frequency = 400MHz band (It is safe for human tissue as I know, I'm not sure 2.4GHz will be ok or not)
    - be able to control and manage data from sensors (around 4 sensors)

    From the research I did, I found that there are some system on chip (SoC) available. It looks convenient, However, it can't be program unless I have the development kits. I only have budget around $200 which is not enough for some development kits. (Please advice if there is other way)

    Can someone please give recommendation for the chips in this case? I have done some arduino project, so I'm familiar with C/C++, it would be better if I can develop using C language.

    Any advice is appreciated.

    Thank you very much.
     
    Last edited: Mar 21, 2012
  2. bertus

    Administrator

    Apr 5, 2008
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  3. Markd77

    Senior Member

    Sep 7, 2009
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  4. zetinal34

    Thread Starter New Member

    Mar 21, 2012
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    Thx a lot guys

    The device will be pill size. as small as possible in this case.

    I checked out the links and really interested in PIC12LF1840T48A

    it is really small and has radio module integrated.

    Could you guys give me some basic guide to start on?
    I will need the development kit correct? which one should I go for..
    What other part I should be looking for..
    My understanding is getting the chip to be programmed by development kit then take the chip and mount it to PCB right?

    Please give me advice, I am really new to this thing

    THank you very much
     
  5. Markd77

    Senior Member

    Sep 7, 2009
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    You will need the PICKIT3 to program it. I suspect that a development board would cause problems with the high frequency at the aerial. I'd suggest making a PCB to match what is on AN1393 (from Microchip site) then you can program it on the board. I've never used an rfPIC but I think that anything but a well designed PCB would not work with 400MHz.
    The rfPIC12F675 family has been around for much longer so would be easier to find code examples and support.
    MPLABX is the new IDE and in my opinion MPLAB 8 is much easier to work with if it supports the chips.
     
  6. nickelflipper

    Active Member

    Jun 2, 2010
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    Not hitting all the requirements, but the Nordic nrf24L01P is certainly small, low power, and modules employing them are really cheap (<$10 ea.). The one advantage is that any micro can control them with SPI commands. Also, there is an Arduino library already made for them, if that is important.

    The disadvantage of the nrf24L01P is that it is 2.4Ghz, low power, and so not going to communicate over distance without some amplifier help. Nordic has sub Ghz parts too, but I don't see them referenced much.
     
  7. zetinal34

    Thread Starter New Member

    Mar 21, 2012
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    I considered Nordic nrf before and I find that the development kit cost 300+ so I have to find other models. Or is there anyway other to program Nordic nrf without development kit?

    I'm sorry for this but I still not sure on the PICKIT3 and also the development kit for rfPIC12F675.
    The development kit will come with the demo board, which has chip installed already. So if I want to program the other chip that I want, can I take off the standard chip and replace it with other chip?
    Moreover, tto build AN1393 which is a transmitter board, I need to program the chip using development kit first? Or I can make the board first then connect to the dev kit?

    Thank you for you advice :) , sorry for this newbie question.
     
  8. nickelflipper

    Active Member

    Jun 2, 2010
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    For the nrf24L01P, there is no programming of the chip, as there is no micro on board, like say the nrf24LE1xxxx. But you need to program a microcontroller (Arduino, Atmel, Microchip, or??) to read and write registers of the rf transceiver chip. So that would be a two chip solution.

    So, for more $$$ you can get the table set for you with a development kit and ready to go demo code. For less $$$ you get to read the data sheet over and over, and piece things together for yourself. Or, hope that someone has developed WORKING code to run on your choice of microcontroller in a language and coding style you understand.
     
  9. Markd77

    Senior Member

    Sep 7, 2009
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    The 675 development kit is basically a PICKIT1 with a couple of transmitter boards and a couple of receiver boards.
    The PICKIT 1 is old and won't program the newer chips like the 1840.
    You could buy the transmitter and receiver boards for the 675 separately and a PICKIT3, which should program them easily and the 1840.
    http://www.microchipdirect.com/ProductSearch.aspx?Keywords=DV164102
    http://www.microchipdirect.com/ProductSearch.aspx?keywords=PG164130
    You unfortunately can't put the 1840 on the 675 transmitter board, but if you build a PCB for the 1840 the PICKIT3 will be able to program and reprogram the chip in situ.
     
  10. zetinal34

    Thread Starter New Member

    Mar 21, 2012
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    I have done more research and now I have two options.

    1) Go for PICkit3 combine with PIC12LF1840T48A
    with this option, I will need to implement PCB board for the chips then find the way to program it right? I'm not quite sure how to use PICkit3 connect with the chip then program it.

    2) Go for TI ez430-rf2500 dev kit
    http://www.ti.com/tool/ez430-rf2500
    With this option, I can program it right away via USB. The problem is if I want to make my own PCB once the prototype works, how can I put the programmed chip to PCB?
    * I also don't see anyone recommend TI chips, is it not good?

    What do you guys think? what is suitable for my project? I have to choose and buy the kits soon.

    Thank you very much
     
  11. nickelflipper

    Active Member

    Jun 2, 2010
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    1) All PICS need to hook up MCLR, Vdd, Vss, ICSPDAT, and ICSPCLK for in circuit serial programming.

    2) That TI kit for $50 is very reasonable. Nothing is the matter with TI products, the TI Launchpad board for $5 is brilliant. I am pretty sure the TI Launchpad has breakout pads that can program those radio modules also, just needs the header to fit. I can't say if the TI solution is best for you, but for development, it looks like an expedient and economical solution.

    In either case, a set of pads or header needs to brought out on the pcb for icsp programming. The other option would be to get the chips preprogrammed prior to board install.
     
  12. panic mode

    Senior Member

    Oct 10, 2011
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    the chip is still about 0.3" x "0.3", then you add batteries etc. eventually this is size of a walnut - not really pill sized. :p
     
  13. zetinal34

    Thread Starter New Member

    Mar 21, 2012
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    Thank you very much guys,

    This is the prototype so it doesn't have to be exactly capsule size, it can be a bit bigger.

    I somehow get this transmitter for free http://www.es.co.th/Schemetic/PDF/TWS-BS3V1.01.PDF
    From the datasheet, I think it is good for my project.
    Do you think it will work?

    Since I got the transmitter, I think I'm going to get the MSP430 LaunchPad Development kit and then buy http://www.ti.com/product/msp430g2211 or http://www.ti.com/product/msp430f2013 (I can't really see the different between this two, can anyone please suggest which one is suitable?)
    Then use the launchPad to program it.
    *Is UART function important to my project? These two chips seem to be lack of it.

    I'm also thinking about an alternative option. Apart from TI product, I also can achieve this by using PIC as well, is there any MCU suggest in this case(to use with my transmitter)?

    Thank you very much
     
  14. nickelflipper

    Active Member

    Jun 2, 2010
    280
    35
    Can't comment on the radio module, but in general the lower the frequency of the radio, the farther the effective range. The opposite is true in terms of data rate, the mentioned radio only has 8Kbs data rate, while the Nordic 2.4gHz modules have up to 2Mbs rate. The low power Nordic modules will only have maybe 30 ft. effective range, so those are the tradeoffs.

    Start development with the higher spec? 2013 and pare down later after becoming familiar with the lineup. Having the hardware uart would be helpful for the debugging process.

    There are almost too many choices on PICs. Get the PICkit 2 or 3 programmer as previously mentioned, along with a demo board, and you are your way. The 18f's are really nice, but most any PIC with enough pins might do the job.

    EDIT: Also if you want to go really small package size, the 2.4gHz modules can do with a pcb antenna, not so sure about the 433Mhz ones, but usually they are pretty big in relative terms.
     
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